Schiltenwolf Marcus, Akbar Michael, Neubauer Eva, Gantz Simone, Flor Herta, Hug Andreas, Wang Haili
Department of Orthopaedic Surgery and Traumatology, University Hospital of Heidelberg, Ruprecht-Karls-University of Heidelberg, Germany.
Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Ruprecht-Karls-University of Heidelberg, Germany.
Scand J Pain. 2017 Oct;17:273-278. doi: 10.1016/j.sjpain.2017.07.019. Epub 2017 Oct 7.
Little is known about the affected cognitive problems in chronic low back pain patients. For this patient cohort research mostly focused on memory of pain, rather than cognitive difficulties related to pain. Chronic pain may be associated with specific (yet undefined) cognitive deficits that affect everyday behaviour. We set out to compare the cognitive function of patients with chronic low back pain (cLBP) in the course of multidisciplinary pain treatments before and after therapy.
Thirty-three patients with cLBP and 25 healthy controls between 20 and 70 years were recruited into the study. The inclusion criteria for patients were: (1) a history of at least 12 weeks of chronic myofascial low back pain without radicular pain sensation before enrolment; (2) grade II and higher chronicity according to von Korff; (3) no opioid medication. The patients recruited had a mean pain duration of 7.13±7.16 years and reported a mean pain intensity of 6.62±2.04 (visual analogue score, VAS). Their mean back function according to the Funktionsfragebogen Hannover (FFbH, a questionnaire comparable with the Health Assessment Questionnaire) was 52.39±20.23%. At three time points (before therapy, 3 weeks and 6 months after therapy) the study subjects were assessed prospectively with a battery of visual memory tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). These included choice reaction time (CRT), pattern recognition memory (PRM) and spatial span (SSP). In parallel, the Trail-Making Test (TMT-A, TMT-B) and the Wechsler Adult Intelligence Scale (WAIS-III) were used to evaluate intelligence and cognitive flexibility.
At the beginning of MDPT (T1), it took patients with cLBP significantly longer than HC to complete TMT-A (38.29±19.99s vs 30.25±14.19s, p=0.047) and TMT-B (72.10±26.98s vs 55.99±22.14s, p=0.034). There were no significant differences between patients and HC in CRT, PRM and SSP. Three weeks (T2) and 6 months (T3) after MDPT, TMT-A reaction time of patients significantly improved by 6.5s and 8.1ms (38.3 ±19.9s vs 31.8±12.3s, p=0.02 and 31.8±12.3s vs 30.2±8.9s, p=0.021, respectively). The patients' working memory was also better 6 months after MDPT (48.8±11.1% at T1, 51.2±11.9% at T2, 57.1±10.9% at T3, p=0.008). Significant correlations among pain, depression/anxiety, medication and neuropsychological tests were found.
These findings show that patients with cLBP have slowed speeds of information processing and working memory, but no alteration in attention and recognition memory. There are clearly interactions of cognitive function with pain, depression, anxiety, and medication. MDPT may improve the impaired cognitive function of patients with cLBP.
Health professionals should contemplate the results from this study when planning therapy strategies especially when prescribing pain medications such opioids to patients with chronic low back pain.
对于慢性下腰痛患者受影响的认知问题了解甚少。针对该患者群体的研究大多集中在疼痛记忆上，而非与疼痛相关的认知困难。慢性疼痛可能与影响日常行为的特定（但尚未明确）认知缺陷有关。我们着手比较慢性下腰痛（cLBP）患者在多学科疼痛治疗前后的认知功能。
招募了33例年龄在20至70岁之间的cLBP患者和25名健康对照者。患者的纳入标准为：（1）入组前有至少12周慢性肌筋膜性下腰痛病史且无神经根性疼痛感觉；（2）根据冯·科夫标准为II级及以上慢性程度；（3）未使用阿片类药物。招募的患者平均疼痛持续时间为7.13±7.16年，平均疼痛强度为6.62±2.04（视觉模拟评分，VAS）。根据汉诺威功能问卷（FFbH，一种与健康评估问卷相当的问卷），他们的平均背部功能为52.39±20.23%。在三个时间点（治疗前、治疗后3周和6个月），使用剑桥神经心理测试自动成套系统（CANTAB）中的一系列视觉记忆测试对研究对象进行前瞻性评估。这些测试包括选择反应时间（CRT）、模式识别记忆（PRM）和空间跨度（SSP）。同时，使用连线测验（TMT-A, TMT-B）和韦氏成人智力量表（WAIS-III）来评估智力和认知灵活性。
在多学科疼痛治疗（MDPT）开始时（T1），cLBP患者完成TMT-A（38.29±19.99秒对30.25±14.19秒，p = 0.047）和TMT-B（72.10±26.98秒对55.99±22.14秒，p = 0.034）所用时间明显长于健康对照者。患者和健康对照者在CRT、PRM和SSP方面无显著差异。MDPT后3周（T2）和6个月（T3），患者的TMT-A反应时间显著改善，分别缩短了6.5秒和8.1毫秒（38.3±19.9秒对31.8±12.3秒，p = 0.02；以及31.8±12.3秒对30.2±8.9秒，p = 0.021）。MDPT后6个月患者的工作记忆也有所改善（T1时为48.8±11.1%，T2时为51.2±11.9%，T3时为57.1±10.9%，p = 0.008）。发现疼痛、抑郁/焦虑、药物治疗与神经心理测试之间存在显著相关性。
这些发现表明，cLBP患者的信息处理速度和工作记忆减慢，但注意力和识别记忆无改变。认知功能与疼痛、抑郁、焦虑和药物治疗之间存在明显的相互作用。MDPT可能改善cLBP患者受损的认知功能。
健康专业人员在制定治疗策略时，尤其是在为慢性下腰痛患者开处诸如阿片类等止痛药物时，应考虑本研究的结果。
